The invention relates to a sensor for switching a pump, in particular a submersible pump or basement pump, on and/or off.
Submersible pumps such as waste water pumps for example, often comprise sensors or switches, which switch on the pump on exceeding a predefined water level, and switch the pump off again when falling short of a second water level, which as a rule is lower. For example mechanical float switches are known for this. However, with these, there is the danger of them becoming blocked in their movement, which leads to faults on switching the pump on and/or off.
Moreover, electronic sensors such as capacitive sensors for switching the pump on and/or off, in dependence on a fluid level or water level, are known. A high-frequency oscillator, which is connected to the water, is provided with these known capacitive sensors. The change of the capacitance formed by the water is thereby determined by way of the electricity consumption of the oscillator. These electronic circuits require a high-frequency signal generator and a very sensitive circuit for detecting the electricity consumption. This renders such switches complicated and expensive.